51 lines
1.2 KiB
ArmAsm
51 lines
1.2 KiB
ArmAsm
global outb
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; outb - Send a byte to an I/O port.
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; stack: [esp + 8] The data byte
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; [esp + 4] The I/O port
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; [esp ] Return address
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outb:
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mov al, [esp + 8] ; Move the data to send into the AL register
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mov dx, [esp + 4] ; Move the address of the I/O port into the DX register
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out dx, al ; Send the data to the I/O port
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ret ; Return
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global inb
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; inb - Returns a byte from the give I/O port.
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; stack: [esp + 4] The address of the I/O port
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; [esp ] The return address
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inb:
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mov dx, [esp + 4] ; Move the address of the I/O port to the dx register
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in al, dx ; Read a byte from the I/O port and store it in the al register
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ret
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global load_gdt
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; load_gdt - Installs a new GDT
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; stack: [esp + 4] The address of the GDT
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; [esp ] The return addess
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load_gdt:
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mov eax, [esp + 4]
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lgdt [eax]
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mov ax, 0x10
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mov ds, ax
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mov es, ax
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mov fs, ax
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mov gs, ax
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mov ss, ax
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jmp 0x08:return ; Perform a "far jump" to load 0x08 in the CS register
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return:
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ret ; Now we've changed CS to 0x08
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global load_idt
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; load_idt - Installs the IDT
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; stack: [esp + 4] The address of the IDT
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; [esp ] The return address
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load_idt:
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mov eax, [esp + 4]
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lidt [eax]
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ret
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